As many high school seniors face a May 1 deadline to decide where to go to college, families are struggling to understand financial-aid letters, which can be murky and confusing. While the federal government requires banks and mortgage companies to disclose interest rates and total payments on loans, financial- aid letters for college - which can cost as much as $240,000 for four years - are unclear about how much families will have to pay. “You have to be savvy enough to know the fine print exists, and then you have to be eagled-eye enough to find it hidden in the letters and on websites,’’ said Debbie Greenberg, a counselor with College Bound St. Louis. The Education Department, consumer groups and guidance counselors are pushing for a standard format for award letters to make them less confusing.